The present invention relates generally to a floor vibration-damping apparatus for a floor of a building on which vibration sensitive office automation equipment, such as computers, is provided, and in particular to a floor vibration-damping apparatus comprising a movable supporting portion for an anti-vibration floor, a damper for attenuation effect and a spring mechanism for restoring effect.
A conventional floor vibration-damping apparatus comprises a movable supporting portion for supporting an anti-vibration floor which is free to move horizontally and a spring damper working portion provided between the anti-vibration floor and a building floor (fixed floor). Such a floor vibration-damping apparatus is disclosed, for example, in Japanese Published Unexamined Patent Application No. 62-86265 (corresponding to U.S. Pat. No. 4,805,359).
In the floor vibration-damping apparatus disclosed in Japanese Published Unexamined Patent Application No. 62-86265, the spring damper is a viscous type damper wherein a shallow and flat vessel is fixed to the fixed floor and accommodates viscous fluid. A resistance plate is submerged in the viscous fluid in parallel with a bottom surface of the vessel and a distance therebetween is a constant. This resistance plate is fixed to the anti-vibration floor. Tension coil springs are provided radially relative to a neutral position of the resistance plate. One end of each tension coil spring is attached to the resistance plate and the opposite end is attached to the fixed floor.
However, in the floor vibration-damping apparatus discussed in Japanese Published Unexamined Patent Application No. 62-86265, the damper working portion includes trigger function means for triggering the damper working portion when receiving a predetermined load. In order to accomplish such a trigger function means, a side wall of the vessel is formed as a reaction receiving portion, and a stiff flat bar is provided between the coil spring and the reaction receiving portion. Moreover, a stopper is mounted on the flat bar such that the stopper touches the reaction receiving portion, and the flat bar is coupled with the neutral position of the resistance plate by a chain. Thus, the damper working portion works mutually in relation to the spring portion and the damper portion, and an operation of establishing the trigger function should be done at a building site. As a result, it is troublesome to assemble the damper working portion, and it takes a long time to set the damper working portion. In addition, it is difficult to make the trigger function with accuracy, and the trigger function affects the damper.
What is desired is a floor vibration-damping apparatus which is free from the aforementioned disadvantages.